Hydrocarbon oil products



United States atent O HYDROCARBON OIL PRODUCTS John Patrick McDermott, Springfield, N. 1., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application December 31, 1952, Serial No. 329,112

2 Claims. (Cl. 252-325) The present invention relates to the improvement of hydrocarbon products derived from petroleum sources and more particularly to the preparation of improved mineral lubricating oil compositions by the incorporation therein of a class of. additives which impart improved properties to such hydrocarbon compositions.

This application is a continuation-in-part of U. S. patent application Serial No. 776,870, filed September 29, 1947,, now abandoned.

In the development of petroleum lubricating oils the trend has been to use more and more eflicient refining methods in order to reduce the tendency of the oils to formv carbon and deposits of solid matter or sludge. While such highly refined oils possess many advantages, their resistance to oxidation particularly under conditions. of. severe service is generally decreased and they are more prone; to form soluble acidic oxidation products which are corrosive. They are generally less effective than the untreated oils in protecting the metal surfaces which they contact against rusting and corrosion due to oxygen and moisture. They also often deposit thickfilms of varnish on hot metal surfaces, such as the pistons of internal combustion engines.

In accordance with the present invention a new class of compoundshas been discovered which when added to refined lubricating oils and other petroleum hydrocarbon products in small proportions substantially reduces the tendency of such oils to corrode the metal surfaces, particularly the surfaces of copper-lead and cadmium-silver bearings which are employed in internal combustion engines, and they are likewise effective in inhibiting oxidation of petroleum hydrocarbon products generally. The products of the present invention are also usefulas detergent additives for internal combustion engine lubricants. Since the products contain no metal, they are particularly useful as ashless detergents in service where ash-forming constituents lead'to harmful'etfects inengines operating under severe conditions, such as in the case of aviation engines.

The compounds of the present invention may be described as nitrogen base salts of alkyl phenol sulfide dithiophosphoric acids having the following general formula:

In this formula R represents at least one alkylradical, preferably having in the range of about 4 to 20 carbon atoms, T represents a nitrogen base radical, and x repice form a phenol sulfide, then reacting the phenol sulfide with a sulfide of phosphorus such as phosphorus pentasulfide, and finally converting the resulting dithiophosphoric acid derivative to a salt by neutralizing the same with a nitrogen base such as ammonia or an amine. The additives of the present invention may be prepared in a light solvent and isolated, or, if they are to be employed as lubricating oil additives, they may be made directly in a lubrication oil medium to form a concentrate containing in the range of 20 to 60% of active ingredient.

Examples of phenols which may be sulfurized and then converted into acids of phosphorus and then new tralized include the simple phenols which are preferably alkylated to provide sufficient oilsolubility in the final product. The alkylated phenols are conveniently prepared by reacting simple phenols with olefinic hydrocarbons such as propylene, butylene, isobutylene, amylenes, diisobutylene, triisobu'tylene, etc., or olefin-containing mixtures obtained in petroleum refining processes as refinery gases.- The reaction of these materials is promoted by means ofa catalyst, such as sulfuric acid. By these means bothmonoalkyland polyalkyl phenols may be prepared and employed in accordance with the present invention. Another class of phenols which may be likewise employed for the purpose of this invention consists of what is known as petroleum phenols, which are obtained by extraction of various petroleum hydrocarbon stocks, chiefly from cracking and heating processes, with caustic soda and acidification of the alkaline extract witha mineral acid, followed by distillation if desired. These petroleum phenols are considered to contain alkyl or cycloalkyl sidechains. Specific phenols which are particularly useful in preparing the salts of the present invention are tert.-amyl phenol, isohexyl phenol, tert.-octyl phenol, di-tert.-amyl phenol, and the like. Phenols containing wax chains or side chains containing cycloaliphaticring structures may also be employed.

The sulfurized phenols employed in accordance With the present invention are prepared by reacting the pheml with a sulfur halide. For example, sulfur monochloride (S2Cl2), is conveniently reacted in proportion of about /2 mol per mol of phenol and preferably in a solvent such as dichlorethane to produce an alkyl phenol disulfide. Using substantially the same procedure but substituting sulfur dichloride (SClz) for the monochloride, thealkyl phenols are given thi'oether linkage substituents. The sulfide of phosphorus employed in the preparation of substituted thiophosphoric acid is preferably phosphorus pentasulfide (P2S5)..

The nitrogen bases which may be employed in the preparation of the salts of the present invention include ammonia and the organic bases. Among the latter, the most useful are the primary and secondary aliphatic amines, but other organic basic materials may be used, such as text-aliphatic amines, aromatic amines, monocyclohexyland dicycloh'exyl amines.- Specific examples of such amines include methylamine, ethylamine, isopropylamine, diisopropylamine, diethylamine, aniline, ethylaniline, benzylamine, ethylnaphthylamine, p-phenylenediamine and theheterocyclic amines, such as pyridine and piperidine. The quaternary ammonium hydroxides may also be employed. Compounds having a guanidine structure, such as guanidine, triphenyl guanidine, and the like, may likewise be employed.

In choosing the reactants for the preparation of a salt in accordance'with the present invention, which is to be employed as an additive'for a mineral oil, consideration should be given'to the oil solubility of the final product. It phenols containing short side chains are employed, it is advisable to employ for the neutralizing reaction an amine containing a'long aliphatic group for the purpose of providing oil solubility. If the solubility is provided in long chains in the phenols, a satisfactory product may be prepared by using ammonia or amines containing only short chains.

The quantity of the additives of the present invention which is most advantageously blended in mineral lubricating oils or other petroleum hydrocarbon products is generally from about 0.1% to 2% by weight when the addi- EXAMPLE I.PREPARATION OF n-BUTYLAMINE TERT.-OCTYLPHENOL SULFIDE DITHIOPHOS- PHATE Product A.Sulfurized tert.-ctylphenol A 4-necked 3 liter flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel was charged with 1.5 liters of ethylene dichloride and 412 g. (2 mol) of tert.-octylphenol (prepared by reacting phenol with diisobutylene in the presence of a catalyst). After the phenol had dissolved, 135 g. (1 mol) of sulfur monochloride was added dropwise from thedropping funnel over a period of 1% hrs. during which time the reaction temperature rose from 25 C. to 38 C., with copious evolution of hydrogen chloride. The reaction solution was stirred under reflux (86 C.) for 18 hours. The solvent was then removed from the product by nitrogen blowing on the steam bath, yielding a straw-colored viscous liquid which analyzed 13.0% S (sulfur).

Product B.-Sulfurized terL-octylpheliol dithiophosphoric acid 379 g. (0.8 mol) of sulfurized terL-octylphenol (Product A) was placed in a 3-necked 2 liter flask equipped with a stirrer, thermometer, and reflux condenser. The viscous material was fluidized by heating to about 70 C., after which 88.8 g. (0.4 mol) of P285 was added. The mixture was heated at 160 C. for 2 hours with rapid stirring, after which it was dissolved in 1 liter of ethylene dichloride and filtered to remove a small amount of unreacted P285. A 15 ml. portion of the solution was poured into an evaporating dish and placed on the steam bath to remove the solvent. A dark sticky solid was obtained which analyzed 4.7% P (phosphorus) and 17.7% S.

Product C.n-Butylamine tert.-octylphenol sulfiide dithiophosphate The reaction solution containing Product B was poured into a 4-necked 2 liter flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, after which 58.4 g. (0.8 mol) of n-butyl amine was added dropwise over a 30 minute period during which time the temperature rose from 28 C. to 46 C. After stirring at room temperature for one hour, the solution was poured into a large evaporating dish and the solvent removed by nitrogen blowing on the steam bath. An amber, tacky solid was obtained which analyzed 14.8% S, 3.9% P, and 2.0% N (nitrogen). The product was completely insoluble in CS2, diflicultly soluble in CCl4, and had a mild odor.

Product D.Hydrolysis of n-butylamine tert.-octylphenol sulfide dithiophosphate A solution of 56.0 g. (0.05 mol) of Product C in 500 ml. of dioxane was placed in a 4-necked 2 liter flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel. Over a 30 minute period, 40 g.

, (1 mol) of NaOH in 200 ml. of

H2O was added dropwise. The reaction mixture was heated at reflux with rapid stirring for 5 hours after which it was placed on the steam bath and evaporated to'dryness. The light yellow pasty mass was mixed with about 400 ml. of hot water and neutralized by the addition of HCl. The aqueous mixture was extracted with 3-200 ml. portions of ether. The ether extract was dried over anhydrous Na2SO4. Evaporation of the solvent yielded a sticky reddish black solid which analyzed 13.9% S, 0.8% I, and 2.3% N. This material was practically odorless. EXAMPLE 2.PREPARATION OF PRIOR ART PRODUCTS In order to obtain a direct comparison of the products A 3-necked 2 liter flask equipped with a stirrer, thermometer and condenser was charged with 412 g. (2 mol) of tert.-octylphenol. After heating to melt the phenol, 111 g. of P2S5 (0.5 mol) was added with stirring after which the reaction mixture was heated at C. for 2 hours. The product was then dissolved in ethylene dichloride and filtered to remove a small amount of unreacted P285. After removal of the solvent on the steam bath, a viscous brown liquid was obtained which analyzed 6.2% P and 9.7% S.

Product F.Reaction of tert.-octylphenol dithiophosphoric acid with sulfur monochloride 430 g. of Product E, tert.-octylphenol dithiophosphoric acid (0.85 mol) was dissolved in 800 ml. of ethylene dichloride. The solution was poured into a 4-necked 2 liter flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel. 57.4 g. of sulfur monochloride (0.425 mol) was then added dropwise over a period of 45 minutes with no temperature rise and a mild evolution of hydrogen chloride. The reaction mixture was heated at reflux (86 C.) with stirring for 18 hours after which the solvent was removed by N2 blowing on the steam bath. A reddish brown tacky solid was obtained which analyzed 5.7% P and 14.8% S.

Product G.Treatment of Product F with n-butylamine Product F was dissolved in 1 liter of ethylene dichloride and the solution was poured into a 4-necked 2 liter flask equipped with a stirrer,- thermometer, reflux condenser and dropping funnel. 62.0 g. (0.85 mol) of n-butylamine was then added over a 30 minute period during which time the temperature rose from 30 C. to 33 C. After stir-ring at room temperature for 1 hour, the solution was poured into an evaporating dish for removal of the solvent. A black viscous liquid was obtained which analyzed 4.7% P, 12.7% S, and 2.2% N. This product was readily soluble in both CS: and CCL; and had a strong disagreeable odor.

Product H .Hydrolysis of Product G This hydrolysis was carried out by the same procedure as described in making Product D using 54.0 g. of Product G. A dark solid was obtained which analyzed 0.3% P, 1.8% N, and 4.3% S and possessed an unpleasant, phenolic odor.

EXAMPLE 3.COMPARISON OF PHYSICAL AND CHEMICAL CHARACTERISTICS OF PRODUCTS C AND G In view of the marked differences in physical and chemical characteristics of the two products, it is possible to draw the following conclusions:

Product C consists chiefly of compounds having-the approximate average formula:

s sn-mNtotm 0 BEN C 2 17 08H CH having the following theoretical analysis: N-1.2 wt. percent, Sl 6.7 wt percent, P5.4 wt.-percent.

The structure ofProduct C arises from the fact that the reaction of a phenol and sulfur halide'is known to form a phenol sulfide containing one-or more sulfur atoms interconnecting benzene nuclei. Subsequent reaction with phosphorus pentasulfide forms the dithiophosphate having an available'sulfhydryl group which in turn reacts with the amine. Evidence of reaction'of the amine and thiophosphate is further shown inthat a temperature rise of 16 C. occurred when the amine was added. Drastic hydrolysis of product C resultedin substantially no reduction of the sulfur content of the'compound. This is characteristic of the sulfur bridge between aromatic nuclei, such bridges not beingrsusceptible to hydrolysis even under severe conditions.

Product G, on the other handyappears to be chiefly a polysulfi-de derivative of diaryldithiophosphoric: acid .in which the hydrogen of the sulfhydryl groups of two molecules :of-the. dithiophosphoric acid, formed by reacting phenol and-P285, is removedyand the two resultingradicals are joined by'oneor more atoms -.of sulfur when reacted with sulfur'halide. Nowacid groupsare available for further reaction. Thisagrees with experimental data. There was no evidence of reaction between the polysultide and the amine since substantiallyno temperature increase occurred when the'two materials were :mixed together. The amine appeared to be present. in a mechanically occluded state or as a loose coordination compound with the polysulfide. Additional evidence that Product G is a polysulfide compound arises from the fact-that drastic hydrolysis of this material, under the identical conditions used in hydrolyzing product C, resulted in a loss of approximately two-thirds of the sulfur content and most of the phosphorus. It is characteristic that the sulfur of such polysulfide structures is relatively loosely bound and is quite susceptible to hydrolysis.

Additional evidence of the marked difierences in chemical structure between products C and G is found in the fact that the former compound was insoluble in carbon disulfide whereas the latter compound was readily soluble inthis solvent.

EXAMPLE 4.-COMPARISON OF LUBRICANT AD- DITIVE' PROPERTIES OF PRODUCTSC AND G Phorone detergency test Blends containing 1% by weight each of products C and G in a paraflinic-type mineral lubricating oil of SAE-3O grade and a sample of the unblended base oil were submitted to adetergencyrtest designed to measure the effectiveness of theadditives for preventing harmful engine deposits in internal combustion engines. The test is conducted as follows: 100 g. of testoil 'are weighed into a clean, 300 cc. tall-form, open glass beaker provided with a stirrer. The beaker is placed in an oil bath maintained at a-temperature of 275 'F. After stirring the test oil for 10 minutes, 10 cc. of phorone and a measured amount of 10% sulfuric acid are added. The mixture is then stirred for one hour during which time a synthetic sludge is formed. The oil is poured off, the beaker-is rinsed with heptane, wiped with a clean cloth to remove loose deposits, dried and'then weighed to determine the amount of tenaciously adhering deposits'remaining in the beaker. The amount of tenaciously adhering deposits correlates with engine deposits formed in heavy duty internal combustion engines operating at relatively high temperatures.

Several runs were carried out on each blend in which the amount of sulfuric acid added was varied. From these data, the phorone number, which is defined as the cubic centimeters of 10% sulfuric acid required to form 10 mgs. of beaker deposits, is determined. A relatively high phorone number is indicative of an additive having good detergency characteristics- The results of the tests follow: TABLE.I.-PHORONE DETERGENCY TEST Beaker Deposit, mgs.

cc.ot10% H2804 Base Oil Base Oil Base Oil 1 a 1 a Product Product O G 48 3 p 22 0 39 0.5 2e 14 Phoronc N 0., ea. 10% 112804110 form 10 mg. beaker deposits 2 2. 1 0. 3

1 Not determined. 1 Obtained by interpolation of plotted data.

It. is seen from this test that Product C is approximately seven times more efl ective in detergency character? istics than Product G at a deposit level of 10 mg. Product G imparted substantially no beneficial detergency properties to the lubricant base stock.

Bearing Corrosion tests Blends containing 0.25 each of the products C and G in an acid-treated naphthenic-type mineral lubricating oil having a viscosity at F. of 355 SUS, and a sample of the unblended base oil, were submitted to a' corrosion test designed to measure the effectiveness of the products-in inhibiting the corrosiveness of a typical min-- eral lubricating oil toward the surfaces of copper-lead bearings. The test was conducted as follows: 500 cc. of the oil was placed in a glass oxidation tube (13 inches long and 2% inches in diameter) fitted at the bottom with a /1 inch air inlet tube perforated to facilitate air distribution. The oxidation tube was then immersed in a heating bath so that the oil temperature was maintained at 325 F during the test. Two quarter sections of automotive bearings of copper-lead alloy of known weight having a total area of 25 sq. cm. were attached to opposite sides of a stainless steel rod which was then immersed in the test'oil and rotated at 600 R. P. M., thus providing sufiicient agitation of the sample during the test. Air was then blown through the oil at therate of 2 cu. ft. per hour. At the end of each 4-hour period the hearings were removed, washed with naphtha and weighed to determine the amount of loss by corrosion. The bearings were then repolished (to increase-the'severity of the test) ,reweighed, and then subjected to the test for additional 4-hour periods in likemanner. The results are given in Table II as corrosion life, which indicates the number of hours 'required for the bearings to lose 100 mg. in weight, determined by interpolation of the data obtained in the various periods.

TABLEIL- t HOUR BEARING CORROSION TEST 4-Hour S. O. D. Life (Hrs. to lose 100 mg./25 sq. cm. Cu-Pb Bearing Surface) Blend Base Oil Base on +0.25% Product ml Base Oil +0.25% Product G H Product C is more than 3.5 times as effective as Product G as a corrosioninhibitor.

EXAMPLE 5.PREPARATION OF ISOPROPYL- AMINE SALT OF TERT.-OCTYL PHENOL SUL- FIDE TI-HOPHOSPHATE sulfide so prepared (containing 1.5 gram atoms of sulfur per mol), and 716 g. of a refined light lubricating oil of approximately SAE10 grade was heated in a 4 liter beaker until a homogeneous solution was obtained (90 C.). 111 g. of P285 was added and the reaction temperature was increased to 140 C. and maintained at this point for 4 hours, followed by filtration to remove a small amount of insoluble material. The filtrate was placed in a 4 liter beaker, and a solution of 118 g. of isopropylarnine in 300 g. of a refined light lubricating oil of approximately SAE-10 grade was added over a 2 hour period, with rapid stirring, the temperature being kept at 4050 C. by means of an ice bath. The product was then left on the steam bath overnight with nitrogen blowing, followed by filtration to remove a slight haze. The product was a dark red, viscous, practically odorless concentrate containing 1.86% phosphorus and 6.92% sulfur. The calculated values for a 40% concentrate of /P\ 0 O @SMQ CsHn CaHr! are 2.01% phosphorus and 7.32% sulfur.

A lubricant blend containing the product of this example was submitted to a bearing corrosion test conducted by the conditions described in Example IV. The base stock employed was an SAE grade paraflinic-type mineral lubricating oil having a bearing corrosion life of 10 hours. This base oil containing 0.25% by weight of the isopropyl amine salt of tert.-octyl phenol sulfide thiophosphate had a bearing corrosion life of 33 hours.

The products of the present invention may be employed not only in ordinary hydrocarbon lubricating oils but also in the heavy duty type of lubricating oils which have been compounded with such detergent type additives as metal soaps, metal petroleum sulfonates, metal phenates, metal alco'holates, metal alkyl phenol sulfides, metal organo phosphates, thiophosphates, phosphites and thiophosphites, metal salicylates, metal xanthates and thioxanthates, metal thiocarbamates, amines and amine derivatives, reaction products of metal phenates and sulfur, re action products of metal phenates and phosphorus sulfides, metal phenol sulfonates, and the like. Thus, the additives of the present invention may be used in lubrieating oils containing such other addition agents as bariurn tert.-octylphenol sulfide, calcium tert.-amylphenol sulfide, nickel oleate, barium stearate, calcium phenyl stearate, zinc diisopropyl salicylate, aluminum naphthenate, calcium cetyl phosphate, barium di-tert.-amylphenol sulfide, calcium petroleum sulfonate, zinc methyl cyclohexyl thiophosphate, calcium dichlorostearate, etc. Other types of additives such as phenols and phenol sulfides may be employed.

The lubricating oil base stocks used in the compositions of this invention may be straight mineral lubricating oils or distillates derived from paraflinic, naphthenic, asphaltic or mixed base crudes, or, if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constituents have been carefully removed. The oils may be refined by conventional methods using acid, alkali and/or clay or other agents such as aluminum chloride, or they may be extracted oils produced, for example, by solvent extraction with solvents of the type of phenol, sulfur dioxide, furfural, dichlorod-iethyl ether, nitrobenzene, crotonaldehyde, etc. Hydrogenated oils or white oils may be employed as well as synthetic oils prepared, for example, by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products. In certain instances cracking coil tar fractions and coal tar or shale oil distillates may also be used. Also, for special application, animal, vegetable or fish oils or their hydrogenated or voltolized products may be employed in admixture with mineral oils.

For the best results the base stock chosen should normally be that oil which without the new additive present gives the optimum performance in the service contemplated. However, since one advantage of the additives is that their use also makes feasible the employment of less satisfactory mineral oils or other oils, no strict rule can be laid down for the choice of the base stock. Certain essentials must of course be observed. The oils must possess the viscosity and volatility characteristics known to be required for the service contemplated. The oil must be a satisfactory solvent for the additive, although in some cases auxiliary solvent agents may be used; 7 The lubricating oils, however they may have been produced, may vary considerably in viscosity and other properties depending upon the particular use for which they are desired, but they usually range from about 40 to 150 sec- 0nd Saybolt viscosity at 210 F. For the lubrication of certain low and medium speed diesel engines the general practice has often been to use a lubricating oil base stock prepared from naphthcnic or aromatic crudes and having a Saybolt viscosity at 210 F. of 45 to seconds and a viscosity index of 0 to 50. However, in certain types of diesel engine and other gasoline engine service, oils of higher viscosity index are often preferred, for example, up to 75 to 100, or even higher, viscosity index.

In addition to the material to be added according to the present invention, other agents may also be used such as dyes, pour depressors, heat thickened fatty oils,.sulfurized fatty oils, organo-metallic compounds, metallic or other soaps, sludge dispersers, antioxidants, thickeners, viscosity index improvers, oiliness agents, resins, rubber, olefin polymers, voltolized fats, voltolized oils, and/or voltolized waxes and colloidal solids such as graphite or zinc oxide, etc. Solvents and assisting agents, such as esters, ketones, alcohols, aldehydes, halogenated or nitrated compounds, and the like may also be employed.

Assisting agents which are particularly desirable as plasticizers and def oamers are the higher alcohols having eight or more carbon atoms and preferably 12 to 20 carbon atoms. The alcohols may be saturated straight and branched chain aliphatic alcohols such as octyl alcohol (CBHI'IOH), lauryl alcohol (C12H25OH), cetyl alcohol (CrsHzaOH), stearyl alcohol, sometimes referred to as octadecyl alcohol (C18H3'IOH), heptadecyl alcohol (C17H35OH), and the like, the corresponding olefinic alcohols such as oleyl alcohol; cyclic alcohols such as naphthenic alcohols; and aryl substituted alkyl alcohols,'for

instance, phenyl octyl alcohol, or octadecyl benzyl alcohol or mixtures of these various alcohols, which may be pure or substantially pure synthetic alcohols. One may also use mixed naturally occurring alcohols such as those found in wool fat (which is known to contain a substantial percentage of alcohols having about 16 to 18 carbon atoms) and in sperm oil (which contains a high percentage of cetyl alcohol); and although it is preferable to isolate the alcohols from those materials, for some purposes, the wool fat, sperm oil or other natural products rich in alcohols may be used per se. Products prepared synthetically by chemical processes may also be used, such as .alcohols prepared by the oxidation of petroleum hydrocarbons, e. g. paraflin wax, petrolatum, etc.

In addition to being employed in crankcase lubricants the additives of the present invention may also be used in extreme pressure lubricants, engine flushing oils, industrial oils, general machinery oils, process oils, rust preventive compositions and greases.

The additives of the present invention may be employed as antioxidant or stabilizing agents not only in mineral lubricating oils, but also in petroleum hydrocarbon products generally, where improved resistance to oxidation is desired. Thus the products may be added to motor oils, diesel fuels, kerosene, waxes, hydrocarbon polymers, etc. and other mineral oils.

The present invention is not to be considered as limited by any of the examples described herein, which are given by way of illustration only, but it is to be limited solely by the terms of the appended claims.

What is claimed is:

1. A lubricating oil composition comprising a major proportion of a mineral lubricating oil and a minor, oxi dation inhibiting amount of a product obtained by react- 10 ing about 2 moles of an alkyl phenol sulfide having the formula:

OH OH R S: R

where R is an alkyl group having in the range of about 4 to 20 carbon atoms and x represents an integer of about 1 to 3, with about 1 mole of P285 at a temperature of about to C. for about 2 to 4 hours, and thereafter reacting the resulting alkyl phenol sulfide-P285 reaction product with about 2 moles of a primary aliphatic amine, selected from the group consisting of n-butylamine and isopropylamine.

2. A lubricating oil composition comprising a major proportion of a mineral lubricating oil and about 0.1 to 2.0% by weight, based on the total composition, of a prodnot obtained by reacting about 2 moles of tert. octyl phenol sulfide with about 1 mole of P285 at a temperature of about 140 to 160 C. for about 2 to 4 hours, and thereafter reacting the resultant tert. octyl phenol sulfide-P285 reaction with about 2 moles of a primary aliphatic amine selected from the group consisting of n-butylarnine and isopropylamine.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL AND A MINOR, OXIDATION INHIBITING AMOUNT OF A PRODUCT OBTAINED BY REACTING ABOUT 2 MOLES OF AN ALKYL PHENOL SULFIDE HAVING THE FORMULA: 